In that Microsoft is promising to bring
Call of Duty to Nintendo players with full feature and content parity, "so they can experience Call of Duty just as Xbox and PlayStation gamers". There are a couple of interesting takeaways in the announcement, one the Nintendo Switch isn't called out specifically, and second - we don't see how something like Call of Duty: Modern Warfare II would run on the aging Switch.
As a 10-Year deal this will of course focus primarily on the Nintendo Switch successor, although there's no word on when that console will arrive. Secondly, it assumes the Activision Blizzard acquisition deal will go through, even though it's currently under fire from all sides in terms of approval.
Like the NVIDIA partnership around cloud gaming, this deal is a clear and impressive step by Xbox to actually bring more choice to the market. With Sony being the most vocal company against the Activision Blizzard merger, its main concern seems to be that Call of Duty will become an Xbox exclusive. Clearly, that's not the plan. At least not anymore.
Also, as Microsoft's Brad Smith states, "We’ve now signed a binding 10-year contract to bring Xbox games to Nintendo’s gamers," this could mean more than just Call of Duty. And that's exciting.